Suspension bridge preassembled abutment towers and anchorage

ABSTRACT

A preassembled abutment tower and anchorage for a combination pontoon and suspension bridge consisting of one or more spans. Each assembly comprises a tower unit of a pair of A-frames connected at their tops by a cross girder. Each A-frame is secured to the deck of a catamaran hulled vessel. Main cables supported by the apices of the A-frames are anchored to opposite shores and hangars support the roadway deck between towers. Anchorage of the catamaran&#39;&#39;s hulls are by cables connecting their prows with anchorage in the bed of the body of water. Spuds, retractable in the A-frames, may also be driven into the bed.

llnited States Patent Marshall et al.

1 1 SUSPENSION BRIDGE PREASSEMBLED ABUTNIENT TOWERS AND ANCHORAGE [72] Inventors: Robert G. Marshall, 8308 Lilac Lane, Alexandria, Va. 22308;

Robert K. Hedrick, 3421 Spring Dr., Alexandria, Va. 22306 22 Filed:

21 Appl. No.: 97,647

Dec. 14, 1970 1 Aug. 22, 1972 FOREIGN PATENTS OR APPLICATIONS 609,501 9/1960 ltaly ..14/27 3,734 1874 Great Britain ..l4/27 Primary E.\'aminer.lacob L. Nackenoll- Attorney-Harry M. Saragovitz, Edward J. Kelly and Herbert Bell 5 7 ABSTRACT A preassembled abutment tower and anchorage for a combination pontoon and suspension bridge consisting of one or more spans. Each assembly comprises a tower unit of a pair of A-frames connected at their tops by a cross girder. Each A-frame is secured to the deck of a catamaran hulled vessel. Main cables supported by the apices of the A-frames are anchored to opposite shores and hangars support the roadway deck between towers, Anchorage of the catamarans hulls are by cables connecting their prows with anchorage in the bed of the body of water. Spuds, retractable in the A-frames, may also be driven into the bed.

5 Claims, 7 Drawing Figures PATENTEDauczz 1912 SHEET 1 0F 2 INVENTOR; Rober G marsh fl Robert KHedricK ATTORNEYS.

PATENTEflAuszzusrz 3,685.0

sum 2 OF 2 m ExToRs, t? G mans h ll Robert K Hedri ck ATTORNEYS.

SUSPENSION BRIDGE PREASSEMBLED ABUTMENT TOWERS AND ANCHORAGE The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to us of any royalty thereon.

This invention relates to suspension bridge preassembled abutment towers and anchorage, and more particularly to the concept of applying the principle of a suspension bridge construction to a pontoon type bridge.

Pontoon type bridges have no support for the main deck, or roadway, between the floating piers and will tend to sag under a heavy vehicle load, even collapse. Also where the bridge is long, many floating piers are necessary to support the bridge load.

The present invention is designed to increase the load capacity of a pontoon type bridge as well as to use fewer floating piers for its support thus resulting in greater economy and faster assembly. The floating piers are provided with a superstructure consisting of a pair of parallel A-frames secured to the deck of a catamaran hulled vessel. Main suspension cables, supported on the apices of the A-frames are anchored at opposite shores and hangar cables attached to the main cables and to the roadway deck provide support between the floating piers. The catamaran vessels are moored by cables to the bed of the body of water or by spuds driven into the bed and retractable in the A- frames.

It is therefore a principal object of this invention to provide a suspension means for supporting the roadway deck of a pontoon type bridge.

Another object is to provide a bridge tower secured on a catamaran hulled vessel for supporting a super structure of a pontoon type bridge.

A further object is to provide a supporting means for the roadway deck of a pontoon type bridge that will reduce the number of floating piers needed for its construction.

A final object is to provide a temporary, semi-permanent or permanent bridge which can be quickly assembled.

These and other objects and advantages of the present invention will be fully apparent from the following description when taken in connection with the annexed drawings, in which:

FIG. 1 is a perspective illustrating the construction of one of the floating piers of the invention;

FIG. 2 is a section taken along line 2-2 of FIG. 1;

FIG. 3 is a detail view showing a modified manner of mounting the A-frame to the deck of a catamaran hulled vessel;

FIG. 4 is a side elevation of a bridge having multiple floating piers for spanning a wide body of water;

FIG. 5 is a detail view of one manner of anchoring a floating pier;

FIG. 6 is a similar view of an alternate anchorage; and,

FIG. 7 is a detail perspective view of a main suspension cable supporting means, drawn to a larger scale.

Referring in detail to the drawings wherein like reference numerals designate like parts throughout the several views, numeral 1 indicates generally one of the floating piers, or bridge tower assemblies used in the construction of the bridge of this invention, see FIG. 1.

The number of assemblies 1 will depend upon the length of the bridge necessary to span the body of water. Each assembly 1 includes a pair of A-frames 2 of box type girders and are arranged in parallel relation. A-frames 2 are connected at their apices by a cross girder 3. The girders may be welded where they join. Each leg of A-frames 2 may be hinged as at 4 to a plate 5 which is secured to the deck 6 of a catamaran vessel including twin hulls 7. The purpose of the hinged connection is to ensure plates 5 to rest flat on deck 6 before securement thereon to provide positive and firm support of the A-frames 2. A pair of main suspension cables 8 are supported, one each by the apex of each A- frame 2 as shown in FIG. 1. The cables 8 are anchored as at 9 to opposite shores by any suitable means, see FIG. 4. Abutting roadway sections 10 are mounted on a footing 11 which rests on deck 6 and may be secured in any suitable manner such as bolts, nails, etc., not shown. The roadway sections 10 are supported between bridge tower units 1 by hangar cables 12, as shown. Any suitable means for supporting cables 8 may be employed and one such method is illustrated best in FIG. 7 and consists of a cap 13 which covers the upper ends of each A-frame 2 as shown. The cable support consists of a block 14 secured to the top of cap 13 having an arcuate groove 15 to provide a guideway to compensate for listing of bridge tower 1 due to rocking caused by waves, traffic, etc. Other supporting means could be used, such as pulleys, etc., not shown if desired.

Means for anchoring hulls 7 are provided and, as best seen in FIG. 5, may consist of a cables 16 secured, one each, to the fore and aft of each hull 7 by an eye bolt 17 and anchored at their free ends to an embedded anchor 18 which may be of ablast driven type anchorage, or by other methods, not shown, to reduce listing of units 1.

Other means for the anchorage of units 1 may be employed. An alternate method is seen in FIG. 6 wherein spuds 19, which may be retractable in A-frames 2, are driven into the body of waters bed 20 as shown. In this case a water tight tube 21 mounted in hull 7 will be used as a guide for the spuds 19 which will pass through plate 5, deck 6, and a hull 7. Both forms of mooring will also insure against sideways drift of the catamaran vessels due to current or tide. The use of retractable spuds 19 provide an excellent means for allowing for rise and fall of units 1 due to changing tides when the bridge is used in tidewaters.

For the purpose of saving time and expense of assembly an alternate method of mounting A-frames 2 on deck 6 may consist of a spear 22 fixed to the lower ends of the legs of A-frame 2. When placed on deck 6, the weight of the superstructure will force spears 22 into the wood of deck 6. This method would sufiice for a short span bridge where only one unit 1 is used and the bridge load is light.

The method of assembling the bridge of this invention is both rapid and simple. A bridge tower unit 1 with its catamaran hulled vessel is towed, as an entity, into position and moored by cables 16, or by driving down spuds 19, to the body of waters bed. The main suspension cables 8 are now placed over the guideways l4 and are tethered to opposite shores. The roadway sections 10 are laid in place and butted over footings 11 and secured thereto by any suitable means. Then the hangars 12 are connected between main cables 8 and roadway sections 10. The bridge is now ready for use. Adjustment means, not shown, may be used to compensate for expansion or contraction of the bridge cables and roadway sections if desired. Such means are well known.

The height of the bridge tower units 1 and the size of the catamaran vessel will depend upon the load to be born by the bridge.

It is apparent that the bridge of this invention affords the simplicity of a pontoon type bridge as well as the load carrying strength of a suspension type bridge and is applicable to temporary, semi-permanent or permanent type of bridge construction. Applications include emergency replacement for washed out bridges or for by-pass bridge while a permanent bridge construction is underway.

What is claimed is:

1. in a combined pontoon and suspension type bridge construction the combination of at least one catamaran hulled vessel having a deck, means mooring said vessel to the bed of a body of water, a framework including supporting legs, means for securing said legs of said framework on said deck, a plurality of roadway sections mounted at their abutting end on said deck, and cable means for the suspension of said roadway sections attached thereto, supported by the ends of said framework and tethered to opposite shores of said body of water, wherein said framework comprises a pair of parallely arranged A-frames, and a cross member joined to the apex of each A-frame, and wherein said means for securing said legs to said deck comprises a plate hinged to the underside of each said leg and secured on said deck.

2. A bridge construction as claimed in claim 1 wherein said catamaran vessel is moored by a cable attached at one of its ends fore and aft of each hull of said vessel and anchored at its other end in the bed of said body of water.

3. A bridge construction as claimed in claim 1 wherein said suspension cables are supported by a cap secured on the apex of each said A-frames and an arcuately grooved block attached on the upper end of each said cap for slidably receiving a main suspension cable therein.

4. A combined pontoon and suspension type bridge for spanning a body of water and comprising at least one vessel having spaced catamaran hulls to rest upon the surface of the body of water and provided with a deck which spans the hulls above the surface of the water, a tower framework which includes spaced pairs of legs, means for securing each leg of each pair to the deck above one of the hulls, a plurality of end-abutting roadway sections secured at their abutting ends to the deck between the legs of the tower framework, the opposite ends of the roadway sections nearest the shores of the body of water being supported by said shores, a pair of spaced suspension cable elements each of which is supported between its ends by the upper end of the tower framework adjacent to one of the pairs of legs, the cables each being tethered to opposite shores of the body of water, supporting members connecting the roadway sections to the cables at spaced points so that the roadway sections are directly supported in part by the cat amaran hulls of the vessel and the shores of the body 0 water and in part by the suspension cables and the supporting members connected thereto, whereby the roadway sections are held out of contact with the surface of the body of water, and mooring means for said catamaran vessel comprising a spud retractable into each leg of said tower framework and being adapted to be driven into the bed of said body of water.

5. A bridge construction as claimed in claim 4 wherein said means for securing said legs to said deck comprises a spear carried by the lower end of each said leg and adapted to be embedded into said deck. 

1. In a combined pontoon and suspension type bridge construction the combination of at least one catamaran hulled vessel having a deck, means mooring said vessel to the bed of a body of water, a framework including supporting legs, means for securing said legs of said framework on said deck, a plurality of roadway sections mounted at their abutting end on said deck, and cable means for the suspension of said roadway sections attached thereto, supported by the ends of said framework and tethered to opposite shores of said body of water, wherein said framework comprises a pair of parallely arranged A-frames, and a cross member joined to the apex of each A-frame, and wherein said means for securing said legs to said deck comprises a plate hinged to the underside of each said leg and secured on said deck.
 2. A bridge construction as claimed in claim 1 wherein said catamaran vessel is moored by a cable attached at one of its ends fore and aft of each hull of said vessel and anchored at its other end in the bed of said body of water.
 3. A bridge construction as claimed in claim 1 wherein said suspension cables are supported by a cap secured on the apex of each said A-frames and an arcuately grooved block attached on the upper end of each said cap for slidably receiving a main suspension cable therein.
 4. A combined pontoon and suspension type bridge for spanning a body of water and comprising at least one vessel having spaced catamaran hulls to rest upon the surface of the body of water and provided with a deck which spans the hulls above the surface of the water, a tower framework which includes spaced pairs of legs, means for securing each leg of each pair to the deck above one of the hulls, a plurality of end-abutting roadway sections secured at their abutting ends to the deck between the legs of the tower framework, the opposite ends of the roadway sections nearest the shores of the body of water being supported by said shores, a pair of spaced suspension cable elements each of which is supported between its ends by the upper end of the tower framework adjacent to one of the pairs of legs, the cables each being tethered to opposite shores of the body of water, supporting members connecting the roadway sections to the cables at spaced points so that the roadway sections are directly supported in part by the catamaran hulls of the vessel and the shores of the body of water and in part by the suspension cables and the supporting members connected thereto, whereby the roadway sections are held out of contact with the surface of the body of water, and mooring means for said catamaran vessel comprising a spud retractable into each leg of said tower framework and being adapted to be driven into the bed of said body of water.
 5. A bridge construction as claimed in claim 4 wherein said means for securing said legs to said deck comprises a spear carried by the lower end of each said leg and adapted to be embedded into said deck. 